ugh u dont make this easy do u... lol
i honestly couldnt tell ya then

.. could be nothing, could be a parasite...
try waiting an extra day for either someone else that might know off the top of their head or to cook the little boogers out... turn up the heat..
turn up your heaters (u should have 2 with a 120) to 85-90 degrees F.. wait one extra day.. i know its hard but for the fishes' sake and for ur pocket money!!
remember to turn it back down tho.. that would be a bad thing to cook the fish.. thats what salmon is for (i dont eat fish ewww!)